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A FX3 client seen as 2 USB devices (SS and HS/FS/LS) | Cypress Semiconductor

A FX3 client seen as 2 USB devices (SS and HS/FS/LS)

Summary: 1 Reply, Latest post by PRJI on 20 Nov 2014 10:47 AM PST
Verified Answers: 1
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Chorwin's picture
14 posts


Is that possible to configure the Cypress FX3 device to allow the USB3.0 and USB2.0 work at the same time? So in Windows, with supported driver, we can see 2 devices attached, where 1 USB3.0 and 1 USB 2.0/1.0 devices.

I seen it possible on some of USB3.0/2.0 PHY chip. Is this possible for FX3? Or there is limitation on FX3 firmware framework that not allow this ? 

prji's picture
Cypress Employee
473 posts


    USB3.0 devices require both USB2.0 (DP and DM lines) and Super Speed (Tx and Rx pairs) data lines to function as a USB3.0 device. USB 2.0 lines are required to provide backward compatibility and error recovery. If the device fails SS communication it falls back to USB2.0 mode and tries USB3.0 connection. So even if you split the upstream lines of a USB3.0 device  to SS and USB2.0 lines, the Host PC wont be able to recover the device in case it fails SS communication.



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